Method of physical downlink control channel monitoring and related device

ABSTRACT

A method for a UE to monitor a PDCCH comprises receiving a first configuration from a base station to configure the UE with a first search space of the PDCCH, where the first search space is used for monitoring a scheduling signal used for indicating scheduling information, receiving a second configuration from the base station to configure the UE with a second search space of the PDCCH, wherein the second search space is used for monitoring a power saving signal used for indicating wake-up information associated with a DRX functionality, monitoring the first search space in response to the UE being in a DRX active time of the DRX functionality, wherein the DRX active time is a time during which the UE monitors the PDCCH, and not monitoring the second search space in response to the UE being in the DRX active time of the DRX functionality.

CROSS-REFERENCE TO RELATED APPLICATION(S)

The present application claims the benefit of and priority to U.S.provisional Patent Application Ser. No. 62/840,451 filed on Apr. 30,2019, entitled “Method and Apparatus of Wake Up Signal Monitoring in aWireless Communication System,” (hereinafter referred to as “the '451provisional”). The disclosure of the '451 provisional is herebyincorporated fully by reference into the present disclosure.

FIELD

The present disclosure generally relates to wireless communications, andmore particularly, to a method of physical downlink control channel(PDCCH) monitoring and a related device.

BACKGROUND

3GPP provides a new study item on a user equipment (UE) power saving innew radio (NR). UE battery life is an important aspect of the user'sexperience, which will influence the adoption of 5G handsets and/orservices. It is critical to study UE power consumption for Rel-16 toensure that UE power efficiency for 5G NR use can be at least as good aslong term evolution (LTE), and techniques and designs for improvementsare identified and adopted.

Because a NR system may be capable of supporting high speed datatransport, it is expected that user data tends to be bursty and providedin very short durations. One efficient UE power saving mechanism is totrigger the UE for network access from a power efficient mode. UE wouldstay in the power efficient mode, such as micro sleep or OFF period inthe long Discontinuous Reception (DRX) cycle, unless it is informed ofnetwork access through a UE power saving framework. Alternatively, thenetwork can assist the UE to switch from the “network access” mode tothe “power efficient” mode when there is no traffic to deliver, e.g.,dynamic UE transition to sleep with network assistance signal.

In addition to minimizing the power consumption with the newwake-up/go-to-sleep mechanism, it is equally important to reduce thepower consumption during the network access in radio resource control(RRC)_CONNECTED mode. More than half of the power consumption in LTE iswith the UE in the access mode. The power saving scheme should focus onminimizing the dominate factor of power consumption during the networkaccess, which includes the processing of aggregated bandwidth, active RFchain number and active reception/transmission time, and dynamictransition to power efficient mode. Since the majority cases of LTEfield transmission time intervals (TTIs) are with no data or smallamounts of data, the power saving scheme for the dynamic adaptation tothe different data arrivals should be studied in RRC_CONNECTED mode.Dynamic adaptation to traffic in different dimensions, such as carrier,antenna, beamforming, and bandwidth, can also be studied for Rel-16.Furthermore, methods to enhance the transitions between “network access”mode and power saving mode should be considered. Both network-assistedand UE-assisted approaches should be considered for UE power savingmechanism.

The study of UE power saving in NR includes the study of the powersaving schemes and the associated procedures. The study of power savingschemes is related to UE adaptation to the traffic and UE powerconsumption characteristics in frequency, time, antenna domains,discontinuous reception (DRX) configuration, and a UE processingtimeline for UE power saving. The power saving signal/channel/procedureis used for triggering adaptation of UE power consumptioncharacteristics. The further study of the power saving signal/channel intriggering UE adaptation to DRX operation is related to theconfiguration of the power saving signal/channel according to the DRXconfiguration as the indication for the UE to wake up from the sleepstate. The further study of the power saving signal/channel candidate intriggering the UE to achieve reduction in PDCCH monitoring is related tousing the power saving signal/channel to trigger UE to skip PDCCHmonitoring and/or to go to sleep for a period of time. For theadaptation to achieve reduction in PDCCH monitoring/decoding, The UEpower consumption can be reduced when the number of UE PDCCH monitoringoccasions and/or the number of PDCCH blind decodings is reduced.

DRX operation is introduced as conventional UE power saving. DRXoperation governs PDCCH monitoring activity of the UE in RRC_CONECTEDmode. When DRX is configured, the UE does not have to continuouslymonitor PDCCH, so power consumption is reduced. FIG. 1 is a schematicdiagram illustrating a DRX operation according to the related art. DRXoperation is characterized by the following:

-   -   on-duration: duration that the UE waits after waking up, to        receive PDCCHs. If the UE successfully decodes a PDCCH, the UE        stays awake and starts the inactivity timer;    -   inactivity-timer: duration that the UE waits to successfully        decode a PDCCH, from the last successful decoding of a PDCCH,        and failing to successfully decode the PDCCH, can go back to        sleep. The UE shall restart the inactivity timer following a        single successful decoding of a PDCCH for a first transmission        only (i.e., not for retransmissions);    -   retransmission-timer: duration until a retransmission can be        expected;    -   DRX cycle: specifies the periodic repetition of the on-duration        followed by a possible period of inactivity;    -   active-time: total duration that the UE monitors PDCCH. This        includes the “on-duration” of the DRX cycle, the time UE is        performing continuous reception while the inactivity timer has        not expired, and the time when the UE is performing continuous        reception while waiting for a retransmission opportunity.

Specifically, a wake-up or a sleep state of the UE could be controlledby DRX mechanism (e.g., DRX Cycle, drx-onDurationTimer,drx-InactivityTimer, drx-StartOffset, etc.). When the UE stays in thewake-up state (e.g., when the UE is in DRX active time), the UE may rampup power to monitor the PDCCH continuously. On the contrary, when the UEis in sleep state (e.g., when the UE is not in active time), the UE maynot need to monitor the PDCCH.

However, the current DRX mechanism still suffers from some drawbacks.For instance, the running drx-InactivityTimer may keep the UE awake evenwithout PDCCH scheduling, or whether or not there is PDCCH scheduling,the drx-onDurationTimer may still periodically trigger the UE to wakeup. This situation may be called PDCCH-only monitoring (i.e., the UEkeeps monitoring the PDCCH but no PDSCH/PUSCH is scheduled for the UE),which causes unnecessary power consumption in RRC connected mode.Therefore, in order to address the shortcoming of current DRX mechanismand save power for the UE, a power saving signal, namely wake-upsignaling (WUS), is introduced.

FIG. 2 is a schematic diagram illustrating a WUS mechanism, inaccordance with related art. The upper part represents a timeline forthe WUS occasion and DRX operation (e.g., DRX cycle and DRX on durationtime), and the lower part represents a level of a UE power consumption.The WUS occasion, which may be a time or frequency resource for WUSmonitoring, may be pre-configured, by a generation node B (gNB), anoffset before the on-duration time. For example, the UE may increase thepower to monitor a WUS on a WUS occasion. If the UE receives the WUSsignal on the WUS occasion, the UE may spend a time to decode the WUSsignal, and then wake up to monitor the PDCCH on the upcoming (or next)on-duration time of the DRX cycle. On the other hand, if the UE does notreceive the WUS signal on the WUS occasion, the UE could switch to thesleep state, namely not wake up to monitor the PDDCH for a period (untilthe next WUS occasion or on-duration time).

The WUS occasion may be indicated by a control resource set (CORESET) orsearch space configuration. For example, the CORESET or search spaceconfiguration of the WUS could be configured along with the DRXconfiguration. In addition, as shown in FIG. 3, the CORESET or searchspace may be a specific CORESET or search space for the purpose of WUSmonitoring (e.g., time and/or frequency resource for monitoring theWUS).

It is possible that the time domain of the CORESET (or search space) forthe WUS may collide with the CORESET (or search space) for scheduling bythe PDCCH, as shown in FIG. 3. For example, in FIG. 4, when the UEreceives a scheduling PDCCH in the on duration of the DRX cycle, the UEmay start or restart a DRX inactivity timer (e.g., drxInactivityTimer).When the DRX inactivity timer is running, the UE may keep monitoring thePDCCH (i.e., the UE stays in DRX active-time). However, if the activetime of the UE overlaps with the on duration of the next DRX cycle(e.g., if an amount of time of the DRX inactivity timer is longer thanthe DRX cycle), the UE may keep monitoring the PDCCH for possiblescheduling until the DRX inactivity timer expires. In this case, the UEmay need to monitor the PDCCH for scheduling as well as the WUS occasionsimultaneously, which increases power consumption of the UE.

SUMMARY

According to an aspect of the present disclosure, a method for a userequipment (UE) monitoring a physical downlink control channel (PDCCH) isdisclosed. The method comprises receiving a first configuration from abase station to configure the UE with a first search space of the PDCCH,wherein the first search space is used for monitoring a schedulingsignal used for indicating scheduling information, receiving a secondconfiguration from the base station to configure the UE with a secondsearch space of the PDCCH, wherein the second search space is used formonitoring a power saving signal used for indicating wake-up informationassociated with a Discontinuous Reception (DRX) functionality,monitoring the first search space in response to the UE being in a DRXactive time of the DRX functionality, wherein the DRX active time is atime during which the UE monitors the PDCCH, and not monitoring thesecond search space in response to the UE being in the DRX active timeof the DRX functionality.

According to an aspect of the present disclosure, a user equipment (UE)monitoring a physical downlink (DL) control channel (PDCCH) in awireless communication system is disclosed. The UE comprises aprocessor, for executing computer-executable instructions, and anon-transitory machine-readable medium, coupled to the processor, forstoring the computer-executable instructions, wherein thecomputer-executable instructions instruct the processor to receive afirst configuration from a base station to configure the UE with a firstsearch space of the PDCCH, wherein the first search space is used formonitoring a scheduling signal used for indicating a schedulinginformation, receive a second configuration from the base station toconfigure the UE with a second search space of the PDCCH, wherein thesecond search space is used for monitoring a power saving signal usedfor indicating wake-up information associated with a DiscontinuousReception (DRX) functionality, monitor the first search space inresponse to the UE being in a DRX active time of the DRX functionality,wherein the DRX active time is a time during which the UE monitors thePDCCH, and not monitoring the second search space in response to the UEbeing in the DRX active time of the DRX functionality.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the exemplary disclosure are best understood from thefollowing detailed description when read with the accompanying figures.Various features are not drawn to scale, dimensions of various featuresmay be arbitrarily increased or reduced for clarity of discussion.

FIG. 1 is a schematic diagram illustrating a DRX cycle, in accordancewith related art methods.

FIG. 2 is a schematic diagram illustrating a WUS mechanism, inaccordance with related art methods.

FIG. 3 is a schematic diagram illustrating a CORESET or search space forscheduling a PDCCH and a WUS, in accordance with related art methods.

FIG. 4 is a schematic diagram illustrating the WUS within DRX activetime, in accordance with related art methods.

FIG. 5 is a flowchart illustrating PDCCH monitoring, in accordance withexample implementations of the present disclosure.

FIG. 6 is a schematic diagram illustrating WUS monitoring, in accordancewith example implementations of the present disclosure.

FIG. 7 is a schematic diagram illustrating WUS monitoring, in accordancewith example implementations of the present disclosure.

FIG. 8 is a block diagram illustrating a node for wirelesscommunication, in accordance with example implementations of the presentdisclosure.

DETAILED DESCRIPTION

The following description contains specific information pertaining toexemplary implementations in the present disclosure. The drawings andtheir accompanying detailed description are directed to exemplaryimplementations. However, the present disclosure is not limited to theseexemplary implementations. Other variations and implementations of thepresent disclosure will occur to those skilled in the art. Unless notedotherwise, like or corresponding elements in the figures may beindicated by like or corresponding reference numerals. Moreover, thedrawings and illustrations are generally not to scale and are notintended to correspond to actual relative dimensions.

For the purpose of consistency and ease of understanding, like featuresare identified (although, in some examples, not shown) by numerals inthe exemplary figures. However, the features in differentimplementations may be different in other respects, and therefore shallnot be narrowly confined to what is shown in the figures.

The phrases “in one implementation,” and “in some implementations,” mayeach refer to one or more of the same or different implementations. Theterm “coupled” is defined as connected, whether directly or indirectlyvia intervening components, and is not necessarily limited to physicalconnections. The term “comprising” means “including, but not necessarilylimited to” and specifically indicates open-ended inclusion ormembership in the described combination, group, series and equivalents.

Additionally, any two or more than two of the following paragraphs,(sub)-bullets, points, actions, behaviors, terms, alternatives,examples, or claims described in the following disclosure may becombined logically, reasonably, and properly to form a specific method.Any sentence, paragraph, (sub)-bullet, point, action, behaviors, terms,or claims described in the following disclosure may be implementedindependently and separately to form a specific method. Dependency,e.g., “based on”, “more specifically”, “preferably”, “In oneembodiment”, “In one implementation”, “In one alternative” or etc., inthe following disclosure is just one possible example which would notrestrict the specific method.

Additionally, for the purposes of explanation and non-limitation,specific details, such as functional entities, techniques, protocols,and standards are set forth for providing an understanding of thedescribed technology. In other examples, detailed description ofwell-known methods, technologies, system, and architectures are omittedso as not to obscure the description with unnecessary details.

Persons skilled in the art will recognize that any described networkfunction(s) or algorithm(s) may be implemented by hardware, software ora combination of software and hardware. Described functions maycorrespond to modules that are software, hardware, firmware, or anycombination thereof. The software implementation may comprise computerexecutable instructions stored on computer readable medium such asmemory or other type of storage devices. For example, one or moremicroprocessors or general-purpose computers with communicationprocessing capability may be programmed with corresponding executableinstructions and carry out the described network function(s) oralgorithm(s). The microprocessors or general-purpose computers may beformed of applications specific integrated circuitry (ASIC),programmable logic arrays, and/or using one or more digital signalprocessor (DSPs). Although some of the disclosed implementations aredirected to software installed and executing on computer hardware,alternative implementations as firmware or as hardware or combination ofhardware and software are well within the scope of the presentdisclosure.

The computer readable medium includes but is not limited to randomaccess memory (RAM), read only memory (ROM), erasable programmableread-only memory (EPROM), electrically erasable programmable read-onlymemory (EEPROM), flash memory, compact disc (CD) read-only memory (CDROM), magnetic cassettes, magnetic tape, magnetic disk storage, or anyother equivalent medium capable of storing computer-readableinstructions.

A radio communication network architecture (e.g., a long term evolution(LTE) system, an LTE-Advanced (LTE-A) system, an LTE-A Pro system, or anNew Radio system) typically includes at least one base station (BS), atleast one UE, and one or more optional network elements that provideconnection with a network. The UE communicates with the network (e.g., acore network (CN), an evolved packet core (EPC) network, an EvolvedUniversal Terrestrial Radio Access Network (RAN) (E-UTRAN), aNext-Generation (GN) Core (NGC), 5G CN (5GC), or an internet via a RANestablished by the BS.

It should be noted that, in the present disclosure, a UE may include,but is not limited to, a mobile station, a mobile terminal or device, auser communication radio terminal. For example, a UE may be a portableradio equipment, that includes, but is not limited to, a mobile phone, atablet, a wearable device, a sensor, or a personal digital assistant(PDA) with wireless communication capability. The UE is configured toreceive and transmit signals over an air interface to one or more cellsin a RAN.

A BS may include, but is not limited to, a node B (NB) as in theUniversal Mobile Telecommunication System (UMTS), an evolved node B(eNB) as in the LTE-A, a radio network controller (RNC) as in the UMTS,a BS controller (BSC) as in the Global System for Mobile communications(GSM)/GSM EDGE RAN (GERAN), an NG-eNB as in an E-UTRA BS in connectionwith the 5GC, a next gNB as in the 5G-RAN, and any other apparatuscapable of controlling radio communication and managing radio resourceswithin a cell. The BS may connect to serve the one or more UEs via aradio interface to the network.

A BS may be configured to provide communication services according to atleast one of the following radio access technologies (RATs): WorldwideInteroperability for Microwave Access (WiMAX), GSM (often referred to as2G), GERAN, General Packet Radio Service (GRPS), UMTS (often referred toas 3G) according to basic wideband-code division multiple access(W-CDMA), high-speed packet access (HSPA), LTE, LTE-A, evolved LTE(eLTE), New Radio (NR, often referred to as 5G), and/or LTE-A Pro.However, the scope of the present disclosure should not be limited tothese protocols.

The BS is operable to provide radio coverage to a specific geographicalarea using a plurality of cells forming the RAN. The BS supports theoperations of the cells. Each cell is operable to provide services to atleast one UE within radio coverage of the cell. More specifically, eachcell (often referred to as a serving cell) provides services to serveone or more UEs within the cell's radio coverage, (e.g., each cellschedules the DL and optionally uplink (UL) resources to at least one UEwithin the cell's radio coverage for DL and optionally UL packettransmissions). The BS can communicate with one or more UEs in the radiocommunication system via the plurality of cells. A cell may allocatesidelink (SL) resources for supporting proximity service (ProSe). Eachcell may have overlapped coverage areas with other cells.

FIG. 5 illustrates a method 500 for a UE to perform PDCCH monitoringaccording to the present disclosure. In action 502, the UE receives afirst configuration from a BS to configure the UE with a first searchspace of the PDCCH, where the first search space is used for monitoringa scheduling signal used for indicating scheduling information on thePDCCH. In action 504, the UE receives a second configuration from the BSto configure the UE with a second search space of the PDCCH, where thesecond search space is used for monitoring a power saving signal usedfor indicating wake-up information associated with a DiscontinuousReception (DRX) functionality on the PDCCH. In action 506, the UEmonitors the first search space in response to the UE being in a DRXactive time of the DRX functionality, where the DRX active time is atime during which the UE monitors the PDCCH. In action 508, the UE doesnot monitor the second search space in response to the UE being in theDRX active time of the DRX functionality.

The method 500 achieves UE power saving by not monitoring the searchspace for scheduling the power saving signal (e.g., WUS) during the DRXactive time. Referring back to FIG. 3, if the CORESETs corresponding tothe two search spaces respectively for a PDCCH monitoring occasion and aWUS monitoring occasion collide in a time domain, the UE is prohibitedto monitor the WUS on the WUS occasion within the DRX active time (e.g.,during drxInactivityTimer running). For example, the UE ignoresmonitoring the WUS on a search space configured for the WUS. Hence, thepower consumption for monitoring the WUS is reduced.

The DRX active time of the UE includes the time while:

the drx-onDurationTimer, drx-InactivityTimer, drx-RetransmissionTimerDL,drx-RetransmissionTimerUL, or ra-ContentionResolutionTimer is running;or

a Scheduling Request is sent on PUCCH and is pending; or

a PDCCH indicating a new transmission addressed to the Cell RadioNetwork Temporary Identifier (C-RNTI) of the Medium Access Control (MAC)entity has not been received after successful reception of a RandomAccess Response (RAR) for the Random Access Preamble not selected by theMAC entity among the contention-based Random Access Preamble.

More specifically, an ongoing Scheduling Request (SR) procedure mayindicate that an SR is sent on the physical uplink control channel(PUCCH) and is pending.

The DRX inactive time may mean the DRX non-active time. Morespecifically, the UE state for only monitoring the WUS may not be calledDRX active time and/or inactive time. The UE state for monitoring theWUS may be a specific state. On the other hand, the UE go-to-sleep statemay indicate that the UE switches to the DRX inactive time (from DRXactive time) or the UE does not monitor a normal PDCCH.

The WUS occasion may be time or frequency resource (e.g., CORESET/searchspace) for the UE to monitor a possible WUS transmitted from the BS. Inone implementation, if the UE unsuccessfully decodes the WUS on the WUSoccasion, the UE may assume that the WUS is not received. Morespecifically, the UE receiving the WUS may mean that the UE successfullymonitors the WUS on the WUS occasion transmitted from the network node(e.g., eNB, gNB, multi-point transmission (TRP) and cell).

In one implementation, the UE may stop the drx-onDurationTimer when theUE receives the WUS on the WUS occasion (in DRX active time or in activetime). The UE may stop the drx-onDurationTimer when the UE does notreceive the WUS on the WUS occasion (in DRX active time or DRX inactivetime). Alternatively, the UE may skip triggering drx-onDurationTimerwhen the UE receives the WUS on the WUS occasion (in DRX active time orinactive time).

More specifically, the UE may not start or restart thedrx-onDurationTimer when the UE receives the WUS on the WUS occasion (inDRX active time or inactive time). Alternatively, the UE may stop thedrx-onDurationTimer when the UE does not receive the WUS on the WUSoccasion (in DRX active time or DRX inactive time).

More specifically, the UE may start or restart the drx-onDurationTimer(on a DRX cycle) when the UE does not monitor and/or receive the WUS onthe WUS occasion (before the DRX cycle), or when the UE is in the DRXactive time.

In one implementation, the UE may stop the drx-InactivityTimer when theUE receives the WUS on the WUS occasion (in DRX active time).Alternatively, the UE may stop the drx-InactivityTimer when the UE doesnot receive the WUS on the WUS occasion (in DRX active time or DRXinactive time).

More specifically, the UE may start or restart the drx-InactivityTimerwhen the UE receives the WUS on the WUS occasion (in DRX active time orDRX inactive time). Alternatively, the UE may start or restart thedrx-InactivityTimer when the UE does not receive the WUS on the WUSoccasion (in DRX active time or DRX inactive time).

More specifically, the UE may stop the drx-HARQ-RTT-TimerDL,drx-RetransmissionTimerDL, and/or ra-ContentionResolutionTimer when theUE receives the WUS on the WUS occasion (in DRX active time or DRXinactive time). Alternatively, the UE may stop the drx-HARQ-RTT-TimerDL,drx-RetransmissionTimerDL, and/or ra-ContentionResolutionTimer when theUE does not receive the WUS on the WUS occasion (in DRX active time orDRX inactive time).

For data scheduling, a network node could determine whether to schedulethe UE with specific timing or not (e.g., based on buffer status of theUE, channel condition, etc.). Therefore, the network node could send aWUS (beforehand) to wake up the UE to monitor the normal PDCCH ifneeded. On the contrary, the network node could also decide not to sendthe WUS if the network node does not schedule UL or DL data transmissionfor the UE. By reducing unnecessary PDCCH monitoring opportunities, theUE could save significant power. More specifically, the UE power for WUSmonitoring may be lower than UE power for normal PDCCH monitoring.

As shown in FIG. 6, the CORESET/search space configured for the WUS andthe normal PDCCH may collide in the time domain. The normal PDDCH may beutilized for scheduling UL/DL data transmission, and the normal PDDCHmay be configured by a PDCCH-configuration. The UE may only monitor oneof the two CORESET/search spaces at a time. For example, when the UE isin DRX active time to monitor the normal PDCCH, the UE may not monitorthe WUS on the WUS occasion. In other words, the monitoring occasion(i.e., CORESETs or search spaces) of the normal PDCCH may be differentfrom the monitoring occasion of the WUS. More specifically, themonitoring occasion of the normal PDCCH and the monitoring of WUS may beassociated with the same serving cell. For example, if the UE is not inDRX active time, the UE may monitor WUS on the WUS occasion. For anotherexample, if the UE receives the WUS on a first WUS occasion, the UE maywake up to monitor the PDCCH and start/restart a drx-InactivityTimerwhen the UE receives a PDCCH for scheduling (e.g., PDCCH for UL/DL datatransmission). If the drx-InactivityTimer is running on a second WUSoccasion, the UE may not monitor the WUS on the second WUS occasion(since the UE is in DRX active time). In addition, the UE may go tosleep when the drx-InactivityTimer expires.

In other words, the purpose of the WUS may be to wake up the UE (e.g.,when the UE receives the WUS), so that the UE may wake up to stay in DRXactive time for monitoring the PDCCH (on next on duration time).However, if the UE is already in the DRX active time, it is unnecessaryto monitor the WUS. Thus, the UE may not need to monitor the WUS whenthe UE is in DRX active time, so as to reduce the power consumption.

Various cases that the UE does not monitor the WUS (i.e., the UE ignoresmonitoring the WUS) are disclosed.

In one implementation, the UE may not monitor the WUS on the WUSoccasion (or ignore monitoring the WUS on the WUS occasion) when the UEis in DRX active time (e.g., duration of drx-InactivityTimer). On thecontrary, the UE may monitor the WUS on the WUS occasion when the UE isnot in DRX active time.

In one implementation, the UE may not monitor the WUS on the WUSoccasion (or ignore monitoring WUS on the WUS occasion) when the UEmonitors the normal PDCCH (e.g., PDCCH for DL/UL scheduling). On thecontrary, the UE may monitor the WUS on the WUS occasion when the UEdoes not monitor the normal PDCCH at that time.

In one implementation, the UE may not monitor the WUS on the WUSoccasion (or ignore monitoring WUS on the WUS occasion) and the normalPDCCH simultaneously.

In some implementations, when the UE detects a beam failure, the UE mayneed to monitor a specific CORESET/search space for beam failurerecovery to find a candidate beam and/or to receive a beam indication(e.g., a transmission configuration indicator (TCI) state indication).In this situation, the UE may not be allowed to monitor theCORESET/search space for the WUS. The UE may stay in DRX active time tomonitor the CORESET/search space for beam failure recovery untilreceiving the PDCCH for a beam indication (e.g., TCI state indication).

More specifically, the UE may not monitor the WUS on the WUS occasion((or ignore monitoring WUS on the WUS occasion)) when the UE performs abeam failure recovery procedure or a random access procedure for beamfailure recovery. It is noted that the UE performing the beam failurerecovery procedure may mean a random access procedure for beam failurerecovery is ongoing (e.g., not consider successfully complete).

In addition, the UE performing a random access procedure may mean aPDCCH indicating a new transmission addressed to the C-RNTI of the MACentity has not been received after successful reception of an RAR forthe Random Access Preamble not selected by the MAC entity among thecontention-based Random Access Preamble.

The WUS may be used to trigger the indication of an RS configuration forchannel tracking, a channel state information (CSI) measurement, andbeam management for the additional assistance of dynamic switching of abandwidth part (BWP) or activation of secondary cell (SCell) inachieving the power saving gain. In addition, the WUS can be used forBWP switching, activation/deactivation of an SCell or adaptation ofPDCCH monitoring and/or CORESET/search space of primary cell(PCell)/SCell. More specifically, the WUS may indicate other information(e.g., cross-slot scheduling, triggering RS transmission, CSI report,single vs. multi-cell operation, BWP, SCell, MIMO layeradaptation/number of Antenna adaptation, indication of CORESET, searchspace or candidate of subsequent PDCCH decoding, PDCCH monitoringperiodicity, PDCCH skipping (skipping duration), DRX configuration, SPSactivation/deactivation). Thus, there are trade-offs on whether the UEshould monitor the WUS occasion when the UE stays in DRX active time.

With reference to FIG. 7, priority of monitoring the WUS and the normalPDCCH is disclosed. In order to save more power, the UE may only beallowed to monitor one of the CORESET/search space of WUS and theCORESET/search space of the normal PDCCH at a time. In other words, theUE may select one of the CORESET/search space to monitor based on acriterion. For example, if the UE monitors the CORESET/search space ofthe WUS, the UE does not monitor the CORESET/search space of the normalPDCCH. On the contrary, if the UE monitors the CORESET/search space ofthe normal PDCCH, the UE does not monitor the CORESET/search space ofthe WUS. Thus, the priority of monitoring the WUS and the normal PDCCHcould be defined or specified in the UE (e.g., based on differentscenarios).

In one implementation, the priority of WUS and the normal PDCCH may bespecified in the specification.

In one implementation, the priority of WUS and the normal PDCCH may bedecided by UE implementation.

Preferably, the priority of the WUS and the normal PDCCH may beconfigured or applied for the UE in RRC connected mode.

Preferably, the priority of monitoring the WUS and the normal PDCCH maybe different in different scenarios.

In one implementation, the priority of monitoring the normal PDCCH maybe higher than monitoring the WUS in one of the following scenarios:

UE is performing a random access procedure;

UE is performing a beam failure recovery procedure;

UE is performing a random access procedure for a beam failure recoveryprocedure;

an SR procedure is ongoing; and

an SR procedure is triggered and pending.

In the other cases, the priority of monitoring the WUS may be higherthan monitoring the normal PDCCH.

As shown in FIG. 7, the left part assumes that the priority ofmonitoring the WUS is higher than monitoring the normal PDCCH. If thetime domain of the normal PDCCH occasion and the WUS occasion collide,the UE may only monitor WUS and could not monitor the normal PDCCH (eventhe UE is in DRX active time). For another example as right part,assuming that the priority of monitoring the normal PDCCH is higher thanmonitoring WUS. If the time domain of the normal PDCCH occasion and theWUS occasion collide, the UE could only monitor the normal PDCCH, andcould not monitor the WUS (on the WUS occasion).

Moreover, various WUS and/or DRX configurations are disclosed.

The WUS may be configured along with the DRX configuration as theindication for the UE to wake up from the sleep state, for triggeringthe UE to skip the PDCCH monitoring and to go to sleep for a period oftime.

More specifically, the UE may monitor the WUS, and determine whether togo to sleep (e.g., not wake up (or not start the drx-onDurationTimer))if the UE receives the WUS based on an indication from a network node.

More specifically, the UE may monitor the WUS, and determine whether togo to sleep (e.g., not wake up (or not start the drx-onDurationTimer))if the UE does receive the WUS based on a network (NW) indication. Inone embodiment, the UE may not go to sleep if the UE does not receivethe WUS on the WUS occasion based on the NW indication. In oneembodiment, the UE may stay in DRX active time (on next on durationtime) if the UE does not receive the WUS on the WUS occasion based onthe NW indication.

In one embodiment, the UE may stay in DRX active if the UE decodes theWUS unsuccessfully.

In one implementation, the UE may be configured with two differentcycles for DRX (e.g., a long DRX cycle and a short DRX cycle). The starttime and/or duration for the short DRX cycle may be configured accordingto the parameters “shortDRX” and/or “drx-ShortCycleTimer”. The starttime and/or duration for the long DRX cycle may be further configuredaccording to the parameter “drx-LongCycleStartOffse”. Since the UE mayswitch the DRX cycles, the WUS occasion may be different based ondifferent DRX cycle. In other words, the UE may be configured withdifferent configurations of the WUS for different DRX cycles. That is,the configuration of the WUS for short DRX cycle and the configurationof the WUS for long DRX cycle are different. More specifically, theconfiguration of the WUS may be associated with the configuration of DRXcycle, where the association may be configured by network.

In addition, the UE may use the long or short DRX cycle based on thefollowing rule. If the UE switches from short/long DRX cycle tolong/short DRX cycle, the UE may determine the WUS occasion based ondifferent DRX cycles and/or different configuration of the WUS.

For example, if the UE uses the short DRX cycle, the UE may use a firstconfiguration of the WUS to determine the WUS occasion. If the UE usesthe long DRX cycle, the UE may use a second configuration of the WUS todetermine the WUS occasion, where the first configuration of the WUS isdifferent from the second configuration of the WUS. More specifically,the UE uses a first configuration to determine the WUS occasion; if thedrx-ShortCycleTimer expires, the UE may use a second configuration todetermine the WUS occasion. On the other hand, the UE uses a firstconfiguration to determine the WUS occasion, if the UE receives a LongDRX Command MAC CE, the UE may use a second configuration to determinethe WUS occasion.

In addition, the UE may apply the same behavior as receiving the DRXcommand when the UE receives the WUS on the WUS occasion (in DRX activetime). Alternatively, the UE may apply the same behavior as receivingthe DRX command when the UE does not receive the WUS on the WUS occasion(in DRX active time).

In one implementation, the WUS may be referred to as a PDCCH-based powersaving signal/channel.

In one implementation, the WUS may be configured with a specificconfiguration for the PDCCH based power saving signal/channel.

In one implementation, the WUS may be a UE-specific or a group commonsignal.

In one implementation, the WUS may be transmitted via a special cell(SpCell), SCell, primary secondary cell (PSCell), or PCell. The WUS maybe indicated as RRC_CONNECTED, RRC_IDLE, or RRC_INACTIVE. Morespecifically, the WUS may be indicated via RRC signaling, MAC signaling(e.g., MAC CE), or PHY signaling (e.g., a DL control information (DCI)).

In one implementation, the WUS may be indicated to switch DL and/or ULBWP. More specifically, the WUS may include BWP information (e.g., a BWPindex).

In one implementation, the WUS may include scheduling information (e.g.,the information for receiving the PDSCH reception or transmitting thePUSCH), cell information (e.g., cell index) and/or beam information(e.g., beam index).

In one implementation, the WUS may include CORESET information (e.g.,CORESET index).

In one implementation, the WUS may be indicated dynamically,periodically, aperiodically, and/or semi-persistently. Morespecifically, the WUS may be indicated via master cell group (MCG) orsecondary cell group (SCG). Moreover, the WUS may be cross-cellindicated. More specifically, the WUS may be indicated on a specificcell and/or BWP.

In one implementation, the UE may derive the WUS occasion based aconfiguration (e.g., RRC configuration). Alternatively, the UE mayderive the WUS occasion based on a pre-defined rule.

Note that, when the UE does not receive the WUS (on the WUS occasion),the UE may not report CSI on the PUCCH until the next WUS occasion,until the UE receives the WUS, or until the next DRX cycle. In addition,when the UE does not receive the WUS (on the WUS occasion or the DRXcycle), the UE may not transmit a sounding reference signal (SRS) untilthe next WUS occasion, until the UE receives the WUS, or until the nextDRX cycle.

FIG. 8 illustrates a node 800 for wireless communication according tothe present disclosure.

As illustrated in FIG. 8, the node 800 may include a transceiver 820, aprocessor 826, memory 828, one or more presentation components 834, andat least one antenna 836. The node 800 may also include an RF spectrumband module, a BS communications module, a network communicationsmodule, and a system communications management module, input/output(I/O) ports, I/O components, and a power supply (not shown). Each ofthese components may be in communication with each other, directly orindirectly, over one or more buses 840. The node 800 may be a UE or a BSthat performs various disclosed functions as illustrated in FIG. 5.

The transceiver 820 includes a transmitter 822 (with transmittingcircuitry) and a receiver 824 (with receiving circuitry) and may beconfigured to transmit and/or receive time and/or frequency resourcepartitioning information. The transceiver 820 may be configured totransmit in different types of subframes and slots including, but notlimited to, usable, non-usable and flexibly usable subframes and slotformats. The transceiver 820 may be configured to receive data andcontrol channels.

The node 800 may include a variety of computer-readable media.Computer-readable media may be any media that can be accessed by thenode 800 and include both volatile and non-volatile media, removable andnon-removable media. Computer-readable media may include computerstorage media and communication media. Computer storage media includesboth volatile and non-volatile, as well as removable and non-removablemedia implemented in any method or technology for storage of informationsuch as computer-readable instructions, data structures, program modulesor other data.

Computer storage media includes RAM, ROM, EEPROM, flash memory or othermemory technology, CD-ROM, digital versatile disks (DVD) or otheroptical disk storage, magnetic cassettes, magnetic tape, magnetic diskstorage or other magnetic storage devices. Computer storage media doesnot include a propagated data signal. Communication media typicallyembodies computer-readable instructions, data structures, programmodules or other data in a modulated data signal such as a carrier waveor other transport mechanism and includes any information deliverymedia. The term “modulated data signal” means a signal that has one ormore of its characteristics set or changed in such a manner as to encodeinformation in the signal. Communication media includes wired media suchas a wired network or direct-wired connection, and wireless media suchas acoustic, radio frequency (RF), infrared and other wireless media.Combinations of any of the disclosed media should be included within thescope of computer-readable media.

The memory 828 may include computer-storage media in the form ofvolatile and/or non-volatile memory. The memory 828 may be removable,non-removable, or a combination thereof. Memory includes solid-statememory, hard drives, and optical-disc drives. As illustrated in FIG. 8,the memory 828 may store computer-readable, computer-executableinstructions 832 (e.g., software codes) that are configured to cause theprocessor 826 (e.g., processing circuitry) to perform various disclosedfunctions. Alternatively, the instructions 832 may be configured tocause the node 800 (e.g., when compiled and executed) to perform variousdisclosed functions.

The processor 826 may include an intelligent hardware device (e.g., acentral processing unit (CPU), a microcontroller, an ASIC, etc). Theprocessor 826 may include memory. The processor 826 may process the data830 and the instructions 832 received from the memory 828, andinformation received via the transceiver 820, the base bandcommunications module, and/or the network communications module. Theprocessor 826 may also process information to be sent to the transceiver820 for transmission via the antenna 836, to the network communicationsmodule for transmission to a CN.

One or more presentation components 834 present data to a person orother device. Presentation components 834 include a display device,speaker, printing component, and vibrating component.

From the previous disclosure, it is evident that various techniques canbe utilized for implementing the concepts of the present disclosurewithout departing from the scope of those concepts. Moreover, while theconcepts have been described with specific reference to certainimplementations, a person of ordinary skill in the art would recognizethat changes can be made in form and detail without departing from thescope of those concepts. As such, the disclosure is to be considered inall respects as illustrative and not restrictive. It should also beunderstood that the present disclosure is not limited to the particulardescribed implementations, but that many rearrangements, modifications,and substitutions are possible without departing from the scope of thepresent disclosure.

What is claimed is:
 1. A method for a user equipment (UE) monitoring aphysical downlink control channel (PDCCH), the method comprising:receiving a first configuration from a base station to configure the UEwith a first search space of the PDCCH, wherein the first search spaceis used for monitoring a scheduling signal used for indicatingscheduling information; receiving a second configuration from the basestation to configure the UE with a second search space of the PDCCH,wherein the second search space is used for monitoring a power savingsignal used for indicating wake-up information associated with aDiscontinuous Reception (DRX) functionality; in response to notreceiving the power saving signal while monitoring the second searchspace, starting a DRX on-duration timer of the DRX functionality;monitoring the first search space in response to the UE being in a DRXactive time of the DRX functionality, wherein the DRX active time is atime during which the UE monitors the PDCCH; and not monitoring thesecond search space in response to the UE being in the DRX active timeof the DRX functionality.
 2. The method of claim 1, wherein the firstsearch space includes at least one of a first time and a first frequencyresource for the UE to monitor the scheduling signal, and the secondsearch space includes at least one of a second time and a secondfrequency resource for the UE to monitor the power saving signal.
 3. Themethod of claim 1, further comprising: determining whether to start aDRX on-duration timer of the DRX functionality according to the wake-upinformation.
 4. The method of claim 1, wherein the power saving signalis further used for indicating a bandwidth part switch of a cell.
 5. Themethod of claim 1, wherein the power saving signal is not received inthe second search space in response to when at least one of the UE doesnot monitor the second search space and the UE unsuccessfully decodesthe power saving signal.
 6. The method of claim 1, wherein the notmonitoring the second search space comprises: not monitoring the secondsearch space while a DRX inactivity timer of the DRX functionality isrunning.
 7. The method of claim 1, further comprising: not monitoringthe second search space in response to the UE performing a random accessprocedure, wherein the UE performs the random access procedure inresponse to one of: a random access response window is running aftertransmitting a first random access preamble; and the UE has not receivedthe scheduling signal on the PDCCH indicating a new transmissionaddressed to a Cell Radio Network Temporary Identifier (C-RNTI) of theUE after successful reception of a random access response correspondingto a second random access preamble not selected by the UE amongcontention-based random access preambles.
 8. The method of claim 1,further comprising: not monitoring the second search space in responseto at least one of the UE performing a beam failure recovery procedureand the UE monitoring a third search space on the PDCCH, wherein thethird search space is configured for the UE to monitor a beam failureresponse from the base station.
 9. The method of claim 1, wherein thepower saving signal is only received from a special cell (SpCell) of thebase station.
 10. A user equipment (UE) monitoring a physical downlink(DL) control channel (PDCCH) in a wireless communication system, the UEcomprising: a processor, for executing computer-executable instructions;and a non-transitory machine-readable medium, coupled to the processor,for storing the computer-executable instructions, wherein thecomputer-executable instructions instruct the processor to: receive afirst configuration from a base station to configure the UE with a firstsearch space of the PDCCH, wherein the first search space is used formonitoring a scheduling signal used for indicating schedulinginformation; receive a second configuration from the base station toconfigure the UE with a second search space of the PDCCH, wherein thesecond search space is used for monitoring a power saving signal usedfor indicating wake-up information associated with a DiscontinuousReception (DRX) functionality; in response to not receiving the powersaving signal while monitoring the second search space, start a DRXon-duration timer of the DRX functionality; monitor the first searchspace in response to the UE being in a DRX active time of the DRXfunctionality, wherein the DRX active time is a time during which the UEmonitors the PDCCH; and not monitoring the second search space inresponse to the UE being in the DRX active time of the DRXfunctionality.
 11. The UE of claim 10, wherein the first search spaceincludes at least one of a first time and a first frequency resource forthe UE to monitor the scheduling signal, and the second search spaceincludes at least one of a second time and a second frequency resourcefor the UE to monitor the power saving signal.
 12. The UE of claim 10,wherein the computer-executable instructions further instruct theprocessor to: determine whether to start a DRX on-duration timer of theDRX functionality according to the wake-up information.
 13. The UE ofclaim 10, wherein the power saving signal is further used for indicatinga bandwidth part switch of a cell.
 14. The UE of claim 10, wherein thecomputer-executable instructions further instruct the processor to: notreceive the power saving signal in the second search space in responseto when at least one of the UE does not monitor the second search spaceand the UE unsuccessfully decodes the power saving signal.
 15. The UE ofclaim 10, wherein the computer-executable instructions further instructthe processor to: not monitor the second search space while a DRXinactivity timer of the DRX functionality is running.
 16. The UE ofclaim 10, wherein the computer-executable instructions further instructthe processor to: not monitoring the second search space in response tothe UE performing a random access procedure, wherein the UE performs therandom access procedure in response to one of: a random access responsewindow is running after transmitting a first random access preamble; andthe UE has not received the scheduling signal on the PDCCH indicating anew transmission addressed to a Cell Radio Network Temporary Identifier(C-RNTI) of the UE after successful reception of a random accessresponse corresponding to a second random access preamble not selectedby the UE among contention-based random access preambles.
 17. The UE ofclaim 10, wherein the computer-executable instructions further instructthe processor to: not monitor the second search space in response to atleast one of the UE performing a beam failure recovery procedure and theUE monitoring a third search space of the PDCCH, wherein the thirdsearch space is configured for the UE to monitor a beam failure responsefrom the base station.
 18. The UE of claim 10, wherein the power savingsignal is only received from a special cell (SpCell) of the basestation.